Circuit breaker with improved frame and cradle support means

ABSTRACT

A circuit breaker comprises improved molded insulating support means for supporting the frame and cradle of the circuit-breaker mechanism.

O Unlted States Patent 1191 1111 3,832,663 Gelzheiser [4 Aug. 27, 1974 [54] CIRCUIT BREAKER WITH IMPROVED 2,953,661 9/1960 Hammerly et a1. 337/54 q 3,088,008 4/1963 337/55 FRAME CRADLE SUPPORT MEANS 3,200,217 8/ 1965 337/54 Inventor: Francis Gelzheiser, Falrfield. 3,475,711 10/1969 Stokes 337/55 Conn.

73 A si ee: Westin house Electric Com an 1 S g" pittsbuggh Pa p Primary Examiner-Harold Broome Attorney, Agent, or Fir m-W. A. Elchik [22] F11ed: Nov. 28, 1973 [21] Appl. N0.: 419,749

52 us. c1 337/112, 335/202, 337/54 [57] ABSIRACT [51] Int. Cl. H0lh 71/02 i [58] Field of Search 337/112, 34, 54, 55; A Clrcwt breaker comprlses Improved molded Insulat- 33 5 202 ing support means for supporting the frame and cradle of the circuit-breaker mechanism. [56] References Cited UNITED STATES PATENTS 5 Claims, 3 Drawing Figures 2,902,560 9/1959 Stanback et a1. 337/54 PAjiminmszmu saw 110; 2

FIG. I.-

FIG. 2.

BACKGROUND OF THE INVENTION mechanism of the general type herein disclosed. This invention is an improvement over the circuit breaker disclosed in the Bullis, .lr., patent in that the housing of the subject circuit breaker is molded to provide improved molded support means for one end of the sup port frame and for one end of the releasable cradle of the operating mechanism.

In the patent to Stanback et al., US. Pat. No. 2,902,560 there is disclosed a circuit breaker of the general type herein-disclosed with the releasable cradle of the operating mechanism supportedon a molded insulating supportpost that is molded integral with a housing part of the circuit breaker. The circuit breaker of the subject invention is an improvement over the Stanback et al. circuit breaker in that a support frame is provided for supporting parts of the circuit breaker including the trip means, and the support'frame and one end of the releasable cradle are supported on improved molded insulating support means formed integral with the housing of the circuit breaker.

SUMMARY OF THE INVENTION A circuit breaker is provided comprising a molded insulating housing and a circuit-breaker mechanism supported in the housing. The mechanism comprises a pair of cooperable contacts and a supporting frame. The insulating housing comprises a side compartment part and a side cover part cooperable with the side compartment part. The compartment part and cover part are molded to provide improved supporting post means for supporting the frame and one end of a cradle that is part of the operating mechanism. The mechanism also comprises trip means that comprises a bimetal member supported on the supporting frame. The cradle, which is pivotally supported in proximity to one end thereof on the support post means, is latched in proximity to the other end thereof by the trip means. Upon the occurrence of overload current conditions above a predetermined value the trip means releases the latched end of the cradle and the cradle is moved to a tripped position to effect automatic opening of the contacts. The housing parts are formed to provide a slot in which the pivot end of the cradle is positioned. Variations in the molded material of the housing from one end of the housing to the other, which could cause a shift in the position of the frame, will also cause the cradle to shift accordingly thereby maintaining a positive predetermined latch engagement between the latched end of the cradle and the trip means.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of a circuit breaker embodying principles of the invention;

FIG. 2 is a sectional view taken generally along the lines Il-II of FIG. 1; and

FIG. 3 is an exploded perspective view, with parts broken away, illustrating the frame, cradle and parts of the housing of the circuit breaker seen in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown, in FIG. 1, a circuit breaker 9 comprising an insulating housing that comprises a molded insulating side compartment part1] and a molded insulating side cover part 13 (FIGS. 2 and 3) secured together by means of four rivets 15 (FIG. 1). A circuit-breaker mechanism, indicated generally at 17, is supported in the housing 11,13. The mechanism 17 comprises a stationary supporting frame 19 fixedly supported in the housing on the housing part 1 l in a manner to be hereinafter more specifically described. The mechanism 17 also comprises a stationary contact 21, a movable contact 23, and trip means indicated generally at 25.

The stationary contact 21 is welded or otherwise fixedly secured toa line terminal 27 that extends out through an opening in the bottom of the housing ll, 13. The movable contact 23 is fixedly secured to one end of a contact arm 29. The contact arm 29, at the upper end thereof, is provided with a depression 31. A molded insulating part 33 of an insulating operating member 35 engages the contact arm 29 in the depression 31 to provide an operative driving connection between the operating handle 35 and the contact arm 29. The operating member 35 is molded with a pair of pin parts 37 at the opposite sides thereof which fit into bearing openings in the housing parts 11 and 13 to support the operating member for pivotal movement on the housing l1, 13. As can be seen in FIG. 1, the operating member 35 comprises a handle part that extends through an opening at the top of the housing 11, 13, to enable manual operation of the circuit breaker. A cradle 41 (FIGS. 1-3) is supported at one end thereof for pivotal movement on the insulating housing in a manner to be herinafter described. The cradle 41, at the other end thereof, is latched by means of the trip means 25 (FIG. 1). An overcenter tension spring 43 is connected at the lower end thereof to a projection 45 on the contact arm 29 and at the upper end thereof to a bentover projection 47 on the cradle 41.

The trip means 25 comprises an elongated bimetal member 49 secured, in proximity to its upper end, to

.a bentover tab part 51 of the frame 19. A flexible conductor 53 is connected at one end hereof to the upper end of the bimetal 49 and at the other end thereof to a conductor 55 that extends through an opening 57 in the housing l1, l3 and is part of a solderless terminal connector 59 that is externally accessible and supported on the housing ll, 13 in a well-known manner. Another flexible conductor 61 is secured at one end thereof to the .lower end of the bimetal 49 and at the other end thereof to the contact arm 29 to electrically connect the contact arm 29 with the bimetal 49.

The circuit through the circuit breaker 9 extends from the line terminal 27, through the stationary contact 21, the movable contact 23, the contact arm 29, the flexible conductor 61, the bimetal 49, the flexible conductor 53, the conductor 55, to a conducting line (not shown) that would be connected to the conductor 55 by means of the solderless terminal connector 59 at an installation.

The circuit breaker 9 may be manually operated to open and close the contacts by operation of the insulating operating handle member 35. Movement of the 'operating member 35 clockwise from the full-line position to the position in which it is shown in broken lines carries the upper end of the contact arm 29 to the left of the line of action of the spring 43 whereupon the spring 43 acts to move the contact arm 29 with a snap action to the open position and shown partially in broken lines in FIG. 1. Movement of the operating member 35 in a counterclockwise direction back to the full-line position moves the upper end of the movable contact arm 29 to the right of the line of action of the spring 43 whereupon the spring acts to move the contact 29, to the closed position with a snap action.

The trip device 25 comprises the bimetal 49, a magnetic yoke 63 and a magnetic armature 65. The yoke 63 is a generally U-shaped member secured to the bimetal 49 at the bight portion of the yoke 63 with the opposite legs thereof facing the armature 65. The magnetic armature 65 is secured to a supportingspring 67 that is secured, at its lower end, to the bimetal 49 whereby the armature 65 is supported on the bimetal 49 by means of the spring 67. The armature 65 has a window opening 71 therein. The one end of the cradle 41 is disposed in the window opening 71 and engages the latch surface 73 of the armature 65 in the latched position shown in FIG. 1.

Upon the occurrence of an overload current above a first predetermined value, the bimetal 49 becomes heated and deflects to the right as seen in FIG. 1 to effect a time delayed thermal tripping operation. The armature 65, which is supported on the bimetal 49 by means of the spring 67, is carried to the right with the bimetal to release the cradle 41. When the cradle 41 is released, the spring 43 acts to rotate the cradle clockwise about an axis 77 until this motion is arrested by the engagement of the cradle 41 with a molded housing part 79 of the housing l1, 13. During this movement, the spring 43 moves the contact arm 29 to the open position and the operating member 35 to an intermediate position intermediate the on and off positions to provide a visual indication that the circuit breaker has tripped opened. The tripped position of the parts is shown in the above-mentioned copending patent application of Stephen A. Mrenna et al.

Before the contacts can be closed following an automatic tripping operation it is necessary to reset and relatch the mechanism. This is accomplished by moving the operating member 35 clockwise from the intermediate position to a position slightly beyond the full open or off position. During this movement, due to the en gagement of a downwardly extending portion 79 of the operating member 35 with the bent-over extension 47 of the cradle 41, the cradle 41 is moved counterclockwise about the axis 77 until the end of the cradle 41 is again'latched in the window opening 71 of the armature 65 on the latch surface 73. Following a resetting operation the circuit breaker can be manually operated in the same manner as was hereinbefore described.

The'circuit breaker is magnetically tripped automatically and instantaneously in response to overload currents above a second predetermined value. Upon the flow-of the overload current through the bimetal 49,

magnetic flux, which is induced around the bimetal, takes the path of least reluctance through the magnetic yoke 63, across an air gap and through the armature 65. When an overload current above the second predetemiined value occurs, the pull of the magnetic flux is of such strength that the armature 65 is attracted to the magnetic yoke 63 whereupon the spring 67 flexes permitting the armature to move to the right to release the cradle 41 whereupon the circuit breaker is tripped open in the same manner as was hereinbefore described with regard to the thermal tripping operation. Following a magnetic tripping operation the circuit breaker is reset and relatched in the same manner as was hereinbefore described.

Improved means is provided for supporting the frame 19 and cradle 41. Referring to FIGS. 1 and 3, it is noted that the frame 19 is provided with an opening 81 in proximity to one end thereof and an opening 83 in proximity to the other end thereof. The molded insulating side compartment part 11 is formed with a molded post 85 and a molded frame support post 87 (FIG. 3) molded integral with the housing part 11. During assembly of the circuit breaker, the frame 19 is pressed onto the post 85 and frame support post 87 which posts fixedly support the stationary frame 19 on the housing part 11. As can be understood with reference to FIG. 3, the frame support post 87 is provided with an extension 89 that keys into an opening 91 in the frame 19. The housing part 11 is also formed with a molded cradle support post 93 having an arcuate surface at the front part thereof. The cradle 41 is formed with a pivot support part 95 (FIG. 3). During assembly of the circuit breaker 9, when the mechanism is mounted on the housing part 11, the cradle 41 is positioned on the cradle support post 93 at the pivot support part 95 and the latch end of the cradle 41 is latched on the armature 65 (FIG. 1). As as hereinbefore described, the cradle 41 pivots on the cradle support 93 (FIG. 3) about the axis 77 (FIG. 1). During assembly of the circuit breaker, after the circuit-breaker mechanism 17 is mounted on the housing part 11 (FIG. 1) the housing cover 13 is moved into position to cooperate with the housing part 11 (FIG. 2) and four rivets 15 (FIG. 1) are applied to rivet the housing parts 11, 13 together to enclose the circuit breaker mechanism. As can be seen in FIG. 3, the molded insulating cover 13 comprises a cover stop part 97 and a cover post part.99. When the cover 13 is secured to the housing part 11 the cover stop part 97 engages the cradle support post (FIG. 2) and the cover post part 99 is spaced from the frame support post 87 to provide a cradle slot 101 in which the cradle 41 moves as the cradle 41 is pivoted to the tripped and reset positions.

The improved frame and cradle support means eliminates an extra bent-over projection in the frame and also a separate insulating member used to support the cradle in prior art structures of the type disclosed in the above-mentioned patent to Bullis, Jr., US. Pat. No. 3,200,217. Referring to FIG. 1, it can be understood that any variation in the molded housing l1, 13, due to warpage or shrinkage of the housing, that would cause a shift of the frame 19 will also cause a shift of the cradle thereby maintaining a positive latch engagement between the cradle 41 and armature 65. Common centers of the opening 83 in the frame 19 and pivot portion 95 of the cradle 41 are provided so that housing warpage will have less effect on latching engagement. With the cover stop part and cradle support post engaging (FIG. 2) and with the cradle post part and frame support post being formed by the same molds, it can be understood that the clearance slot 101 (FIG. 2) for the movable cradle 41 will be constant in the quantity production of circuit breakers that would be manufactured with the use of the same molds. With the cover stop part and cradle support posts being in proximity to the one rivet (FIG. 1) these parts will engage under the force of the rivets that secure the housing parts together.

I claim:

1. A circuit breaker comprising a molded insulating housing, a circuit-breaker mechanism supported in said housing, said mechanism comprising a pair of cooperable contacts, a supporting frame, said housing comprising molded insulating support means supporting said supporting frame on said housing, trip means comprising a bimetal member supported on said supporting frame, a releasable cradle supported for pivotal movement in proximity to one end thereof on said molded insulating support means and latched in proximity to the other end thereof on said trip means, upon the occurrence of overload current conditions above a predetermined value said trip means automatically releasing said cradle whereupon said cradle pivots to a tripped position to effect automatic opening of said contacts, said insulating support means comprising a molded insulating frame support post and a molded insulating cradle support post in proximity to said molded insulating frame support post, said supporting frame in proximity to said one end thereof being supported on said frame support post, and said cradle in proximity to said one end thereof being pivotally supported on said cradle support post.

2. A circuit breaker according to claim 1 and said cradle being pivotally supported on said cradle support post in a slot formed in said insulating housing.

3. A circuit breaker according to claim 2, said insulating housing comprising a side compartment part and a side cover part cooperating with said side compartment part, said first and second insulating support means being molded integral with said side compart ment part, said cover part comprising a cover stop part and a cover post part molded integrally therewith, said compartment part and said cover part being constructed and arranged such that when said compartment and said cover part are secured together said cover stop part engages said cradle post part with said cover post part spaced from said frame support post to provide said slot in which said cradle is pivotally supported.

4. A circuit breaker according to claim 3, and said frame being pressed-fitted on said frame support post in a stationary position.

5. A circuit breaker according to claim 3, said cradle and said cradle support post and said frame support post being constructed such that the center line through said cradle support post is substantially coexistent with the center line through said frame support post. 

1. A circuit breaker comprising a molded insulating housing, a circuit-breaker mechanism supported in said housing, said mechanism comprising a pair of cooperable contacts, a supporting frame, said housing comprising molded insulating support means supporting said supporting frame on said housing, trip means comprising a bimetal member supported on said supporting frame, a releasable cradle supported for pivotal movement in proximity to one end thereof on said molded insulating support means and latched in proximity to the other end thereof on said trip means, upon the occurrence of overload current conditions above a predetermined value said trip means automatically releasing said cradle whereupon said cradle pivots to a tripped position to effect automatic opening of said contacts, said insulating support means comprising a molded insulating frame support post and a molded insulating cradle support post in proximity to said molded insulating frame support post, said supporting frame in proximity to said one end thereof being supported on said frame support post, and said cradle in proximity to said one end thereof being pivotally supported on said cradle support post.
 2. A circuit breaker according to claim 1 and said cradle being pivotally supported on said cradle support post in a slot formed in said insulating housing.
 3. A circuit breaker according to cLaim 2, said insulating housing comprising a side compartment part and a side cover part cooperating with said side compartment part, said first and second insulating support means being molded integral with said side compartment part, said cover part comprising a cover stop part and a cover post part molded integrally therewith, said compartment part and said cover part being constructed and arranged such that when said compartment and said cover part are secured together said cover stop part engages said cradle post part with said cover post part spaced from said frame support post to provide said slot in which said cradle is pivotally supported.
 4. A circuit breaker according to claim 3, and said frame being pressed-fitted on said frame support post in a stationary position.
 5. A circuit breaker according to claim 3, said cradle and said cradle support post and said frame support post being constructed such that the center line through said cradle support post is substantially coexistent with the center line through said frame support post. 